Analysis of related factors of long-term complications after vascularized fibular transplantation.

OBJECTIVES: Free fibula flap is the first choice for jaw reconstruction in head and neck oncology, but postoperative complications in donor site are ignored always. The main purpose of this study was to investigate the long-term complications and potential risk factors of donor site after vascularized fibular transplantation, and to explore the precautions of preparing vascularized fibular flap and the measures of preventing donor site complications. MATERIALS AND METHODS: Data were retrospectively collected on 31 patients who had undergone immediate mandibular reconstruction with a fibular flap after segmental mandibulectomy from 2013 to 2018 in Shanghai Ninth People's Hospital. Thirty-one patients (24 male, 7 female) were available for the long-term complications in donor site analysis from 25 to 96 months after surgery. The data were collected and analyzed, including age at time of operation, early postoperative complications, incidence of dorsiflexion weakness of hallux, donor site missing fibula length, proximal and distal stump fibula length, and subjective evaluation of foot function (AOFAS-hallux, AOFAS-ankle hindfoot, Enneking lower limb function score). In the single-factor analysis in this study, the correlation between related factors and long-term complications was statistically analyzed. For inter-group comparisons of quantitative data, if the normal distribution was satisfied, two independent sample t-tests were used; p < 0.05 was statistical significant. If the normal distribution was not satisfied, Wilcoxon rank-sum test was used, and p < 0.05 was considered statistically significant. For qualitative data, the Fisher exact probability method was compared between group differences, and p < 0.05 was statistically significant. RESULTS: The most commonly encountered complication in our series was dorsiflexion disorder, flexion deformity, numbness of the lateral side of the lower leg, and dorsum of the foot. Ten patients (32.26%) developed hallux flexion deformity after operation, 17 patients (54.84%) had hallux dorsiflexion dysfunction after operation, and 10 patients (32.26%) had numbness of the lateral side of the lower leg and dorsum of the foot. The incidence of hallux dorsiflexion dysfunction, thumb flexion deformity, and sensory disturbance was higher than that of other long-term complications in the donor area. The residual length of fibular distal was related to the dorsiflexion dysfunction and flexion deformity of hallux (p < 0.05). The early complications of donor site were correlated with the hallux dorsiflexion dysfunction (p < 0.05). CONCLUSIONS: The incidence of dorsiflexion disorder and flexion deformity is higher in patients after fibula transplantation. The less the residual length of fibular distal, the more obvious the long-term complications in the donor site, and the higher the incidence of dorsiflexion dysfunction and flexion deformity of hallux. CLINICAL RELEVANCE: The long-term complications of donor site after fibular transplantation seriously affect the quality of life of patients and provide clinical reference for further reducing the occurrence of donor site complications.

Differential impacts of microplastics on carbon and nitrogen cycling in plant-soil systems: A meta-analysis.

Microplastics (MPs) are widely present in terrestrial ecosystems. However, how MPs impact carbon (C) and nitrogen (N) cycling within plant-soil system is still poorly understood. Here, we conducted a meta-analysis utilizing 3338 paired observations from 180 publications to estimate the effects of MPs on plant growth (biomass, nitrogen content, nitrogen uptake and nitrogen use efficiency), change in soil C content (total carbon (TC), soil organic carbon (SOC), dissolved organic carbon (DOC), microbial biomass carbon (MBC)), C losses (carbon dioxide (CO2) and methane), soil N content (total nitrogen, dissolved organic nitrogen, microbial biomass nitrogen, total dissolve nitrogen, ammonium, nitrate (NO3--N) and nitrite) and nitrogen losses (nitrous oxide, ammonia (NH3) volatilization and N leaching) comprehensively. Results showed that although MPs significantly increased CO2 emissions by 25.7 %, they also increased TC, SOC, MBC, DOC and CO2 by 53.3 %, 25.4 %, 19.6 % and 24.7 %, respectively, and thus increased soil carbon sink capacity. However, MPs significantly decreased NO3--N and NH3 volatilization by 14.7 % and 43.3 %, respectively. Meanwhile, MPs significantly decreased plant aboveground biomass, whereas no significant changes were detected in plant belowground biomass and plant N content. The impacts of MPs on soil C, N and plant growth varied depending on MP types, sizes, concentrations, and experimental durations, in part influenced by initial soil properties. Overall, although MPs enhanced soil carbon sink capacity, they may pose a significant threat to future agricultural productivity.

Machine learning algorithm based on jaw feature points assist complex maxillary and mandibular reconstruction.

PURPOSES: Large-scale jaw reconstruction can hardly achieve satisfactory results only by relying on doctors' experience. In this study, we assessed a new approach using a machine learning algorithm based on jaw feature points to assist complex jaw reconstruction in patients with maxillary and mandibular defects. METHODS: One hundred and two computed tomography (CT) data on the jaw were collected and 16 skeletal marker points on the jaw were selected. The machine learning algorithm learned the positional relationship between points and built a model, which was used to predict the coordinate position of an unknown point. Then the model was used for a surgical plan in clinical cases. RESULTS: The linear regression model based on machine learning can control the error within 3 mm. In linear models, Lasso has a slight advantage over the others. We used Lasso to predict the missing points for two patients with maxillary and mandibular defect, respectively. The operation was carried out as planned, and the defects were successfully repaired. CONCLUSIONS: The restoration of jaw feature points based on a machine learning algorithm is expected to solve large-scale jaw defects without contralateral reference.